The present invention relates to spray dryers which are used to provide particulate or powdery materials by contacting fine droplets of a solution or slurry containing the materials with a hot fluid blast.
After a spray dryer has been used to produce particles or powders of a certain material, it is often used to produce particles or powders of a different material. However, if the spray dryer is not cleaned between these treatments, the products of the subsequent treatment can become contaminated with residual products from the prior treatment, i.e., due to previous particulate or powdery materials becoming temporarily stuck inside the tank. However, cleaning conventional spray dryers between treatments of differing materials has been a problem because such dryers are stationary secured to a base frame, and since the tank has only a product trap port in its bottom section and a small door in its one side surface which serves also as an observing window, the tank must be cleaned through the door which serves as the observing window. As such, the cleaning work is very difficult and results in the cleaning personnel becoming quite dirty. Further, the upper corner parts inside of the tank, which are at dead angles relative to the cleaning personnel, cannot be properly cleaned.
The present spray dryer has been devised in view of the above-mentioned defects inherent in conventional spray dryers so as to provide a spray dryer which facilitates the cleaning of the inside of a tank and the removal of a previous material product when the sprayer is to be used to produce a subsequent (different) material product
According to the present invention, the spray dryer includes a tank having an upper end which is open and which is rotatably mounted on a base frame, and an upper cover which is attached to the tank and is movable to close the tank when in use and to open the tank (and provide access inside) when spray drying in the tank has been stopped and it has been rotated for cleaning.
Further features and advantages of the invention will be recognized by reference to the accompanying drawings, taken in conjunction with the following discussion.